This invention relates to an electrical coil module, an electrical coil comprising such modules, an actuation mechanism including such a coil an a circuit breaker comprising such an actuation mechanism. The present actuation mechanism is preferably used in circuit breakers especially for protection of DC installations such as traction networks including the rail vehicles. The circuit breaker is typically used for limiting current in case of short circuit somewhere In the installation. It has, however, also numerous other industrial applications.
A hybrid breaker stands for a circuit breaker making use of the successive action of a very fast mechanical system and a static circuit breaker.
It Is possible to distinguish three different categories of circuit breakers for DC.
The electromechanical circuit breaker, the static circuit breaker and the hybrid circuit breaker.
The first type of circuit breaker, the electromechanical circuit breaker, is today used in most of the feeding stations and rail vehicles in traction systems.
This type has, howev r, sev ral inconveniences such as high wear, high noise level, a relativ ly long reaction tim , high maint nance costs, etc.
The static circuit breaker has been the object of numerous tests, studies and realisations on a laboratory scale but the high dissipation during normal operation makes it unusable for commercial exploitation.
The last type of circuit breaker, the hybrid breaker, has its name from th combination of an electromechanical system and power electronics. During normal working conditions the current is conducted through a mechanical connector having very low losses. When activated the mechanical connector disconnects and the current is taken over by a static breaker connected in parallel. Once the mechanical connector has completely disconnected the static part is breaking the current through the circuit. Due to the fast operation of th mechanical system and the commutation of the current the arc created over the mechanical contacts is limited.
Several different realisatons are possible. One known solution uses the injection of current in the opposite direction of the short circuit current by means of the discharge of a capacitor. This type has been the object of numerous tests and realisations. Its complexity, price and lack of reliability have, however, prevent d its commercial success.
One object of the present invention is to provide an electrical coil module of planar type preferably manufactured by means of printed circuit techniques on a generally flat substrate.
It is a further object of the invention to provide an extremely thin and compact electrical coil making us of such coil modules which is especially advantageous as a driving means in a so called Thomson mechanism forming part of a circuit breaker. This type of coil has also other applications.
A further object of the present invention is to provide a circuit breaker of the hybrid type which is extremely fast and efficient.
An advantageous embodiment of the circuit breaker is characterised by a new design of the eletromechanical actuation mechanism and an especially compact and symmetrical design of the static part of the breaker.
An important advantage with the circuit breaker according to the invention is that the dissipation is extremely low. The noise level when actuated is also very low. The new design of the actuation mechanism for the mechanical contact has increased the speed of the mechanism and made it very compact. Reliability and life time of the breaker are excellent.
Other objects, uses and advantages of this invention will be apparent from the reading of this description which proceeds with reference to the accompanying drawings forming part thereof and wherein:
FIG. 1 schematically shows a hybrid circuit breaker according to the present invention,
FIG. 2 schematically shows the electromechanical part of the circuit breaker,
FIG. 3a and 3b show different views of a coil module of planar type forming part of a first embodiment of the coil in the drive mechanism of the electromechanical part of the circuit breaker,
FIG. 3c shows an isolating element to be placed between two successive coil modules according to FIGS. 3a and 3b, 
FIG. 4a-4d show different views of two coil modules of planar type forming part of a second embodiment of the coil in the drive mechanism of the electromechanical part of the circuit breaker,
FIG. 5 shows the electrical and mechanical arrangement of the components of the static part of the circuit breaker,
FIG. 6 shows another electrical and mechanical arrangement of the components of the static part of the circuit breaker,
FIG. 7 shows a MOVxe2x80x94resistor combination efficient to reduce the cost of the MOV by distributing the energy.
FIG. 8 schematically shows the locking mechanism of the electromechanical part of the circuit breaker,
FIG. 9a and 9b show side views of the contact and drive mechanism of one embodiment of the invention.